Compounded oil



Patented Oct. 5, 1948 COMPOUNDS!) 0114 James 0. Clayton, Berkeley, Califalsignor to California Research Corporation, San Franoisoo, Calif acorporation of Delaware No Drawing. Application October 31, 1944 SerialNo. 561,317 c dclaiml.

This invention relates to lubricants and the like. more particularly, tocrankcase lubricants such as those used in the ordinary motor car, inaircraft engines and in Diesel engines.

crankcase lubricants are required to maintain lubrication of pistonsunder severe conditions. Temperatures are such and the oxidizingcharacter of the combustion gases (which are hot and under pressure) issuch that mineral lubricants decompose forming products which arecorrosive and products which ioul the piston, interfere with passage oflubricant through the openings in the oil ring and cause sticking. ofpiston rings. In certain types of service, as in heavy Diesel engines,straight mineral lubricants, regardless of selection of crude oil andregardless of the refining procedure, will not stand up under theconditions imposed for a reasonably long period of operation. Added tothe eiiects of lubrlcant deterioration are deposits formed by the fuelused to operate the engine.

It is now a common practice to add to mineral lubricants one or moreagents adapted to stafbilize the oil. reduce the amount oi depositson'fl pistons, etc. Seldom is it suilicient, howeverfto add only. onetype of addition agent. 'Thus a strongly detergent addition agent (thatis, an

addition agent which promotes engine cleanliness) may not adequatelystabilize the oil and may allow development of corrosive oxidationproducts in the oil. Many detergents are'corrosive to cadmium-silverbearings and certain of them cause the oil to foam excessively underconditions of violent agitation with air and at low pressures.

It is an object achieved by the present invention to provide acombination of addition agents for lubricating oils and the like whichis inexpensive and at the same time eilects substantial improvement ofthe oil.

It is a particular object achieved by the present invention to provide acrankcase lubricant suitable for heavy duty use which combines highdetergent qualities, low corrosiveness and reduced ioaminess.

These and other objects will be apparent from the following descriptionand the claims.

I have discovered that lubricating oils and the like can be greatlyimproved by adding thereto 2 a salt of a sulfonic acid and a salt of athiscarbamic acid.

The base oil to which the sulfonic and thiccarbamic salts are added willusually be a petroleum oil of lubricating viscosity. It may range inviscosity from spindle oils to cylinder stocks; it

may be from a paraiflnic, naphthenic or mixed base crude petroleum; itmay be refined by any or several of various methods. may be a distillateor residual oil, etc.

However. the base oil may consist in whole or in part of other oils,such as certain vegetable oils (e. g., castor oil. sperm oil)polymerized oleiins, oils synthesized from coal or oxides of carbon,amyl naphthalene, etc.

The sulfonic acid whose salt is added to the base ,oil (or formed insitu) may be a pure compound but will usually be a mixture. often acomplex mixture of sulfonic acids. The so-called mahogany acids arepreferred. These are high molecular. weight, oil-soluble acids formed inthe refining oi mineral lubricating ofls with strong or fuming sulfuricacid to produce medicinal or technical white oil. On heavy treatment ofsuch mineral oil with sulfuric acid two phases are formed, one of which(the lower, heavy layer) is a sludge and the other (the upper layer)consists of the treated oil containing the mahogany acids. The sludgecontains the so-called green acids, which are water-soluble asdistinguished from oil-soluble acids. The mahogany acids may berecovered from the oily phase by various methods. Thus the oily layermay be extracted with aqueous methyl, ethyl or isopropyl alcohol toextract the mahogany acids. Or the oily layer may be neutralized withaqueous alkali and the alkali metal mahogany sulfonates extracted withaqueous methyl, ethyl or isopropyl alcohol or aqueous acetone.

Methods of recovering mahogany acids and their alkali metal salts arewell known in the art and further elaboration is not required hereexcept to note that, in connection with the pres-' though suli'onicacids of molecular weight of 350 or lower can be used in certain typesof service. By aliphatic type su-lfonic acids is meant sulionic acids inwhich at least about 50 per cent by weight of the sulfonic acid consistsoi aliphatic carbon and hydrogen; it does not mean that the sulfonicacid is necessarily a true allphatic sulionic acid wherein the suifonicgroup or.groups is or are attached only to aliphatic carbon. Thus,besides the mahogany sulionic acids there may be used benzene,naphthalene and other sulionic acids in which one or more oilsolubilizing, preferably long chain allryl substituents are attached tothe aromatic nucleus. Examples of such aliphatic substituted aromaticsulforiic acids are the salts of cetyi benzene sulfonic acid, cetylnaphthalene sulfonic acid, the sulionic acids described in Flett; UnitedStates Patent No. 2,283,199, and other sulionic acids repared fromaromatic hydrocarbons containg aliphatic radicals derivable frompetroleum.

Although nitrogen base and alkali metal sulfonates may be used,polyvalent metal sulionates are preferred and of the polyvalent metalsulfcnates those of the more basic metals, such as magnesium, calcium,strontium andbarium are preferred.

Examples of sulionates that may be used in accordance with the inventionare lithium, potassium, sodium, calcium, barium, aluminum, zinc, tin andlead mahogany sulfonates, cetyl benzene sulionates and cetyl naphthalenesulionates; the corresponding salts of the sulionic acids described inFlett, United States Patent No. 2,283,199; the corresponding salts ofsulfonic acids prepared from aromatic hydrocarbons containing aliphaticradicals derivable from petroleum; and true allphatic sulionates, ,suchas lithium, potassium, sodium, calcium, barium, aluminum, zinc, tin andlead sulfonates derivable from the product of condensing chlorinatedpetroleum wax with sodium acid sulfite.

A solution of calcium mahogany sulionate in lubricating oil can beprepared as follows: Take an acid treated oil, preferably at a latestage in the acid treatment and extract the sulfonic acids from the oilby means of ethyl alcohol. Add a petroleum thinner and water to thealcoholic extract and allow the aqueous phase and the petroleum thinnerphase to separate; the latter phase will contain the suli'onic acids.Add to the petroleum thinner solution of sulfonic acids, calciumhydroxide in quantity suilicient to neutralize the sulfonic acids andlubricating oil in quantity suflicient to prepare a concentrate oi theresultant calcium sulfonate. Filter the mixture and remove the lightsolvent by distillation, leaving a residue of lubricating oil in whichthe calcium suli'onate is dissolved.

The thiocarbamates, which form the second component of the compoundingof the invention, may be represented generically by the formula Thepreferred thiocarbamates are the polyvaient metal dithiocarbamates inwhich R1 and R: are both hydrocarbon or substituted hydrocarbon groupswhich are suillciently large v(e. g., 4 to 20 carbon atoms each) toimpart oil solubility to the dithiocarbamate, or in which R1 and R: area single bivalent hydrocarbon group as in the petroleum base"dithiocarbamates discussed hereinbelow. The preierred polyvaient metalsare zinc and cadmium. Among other metals that may be used are lithium,sodium, potassium, magnesium, calcium, strontium, barium, aluminum. tinand lead.

The dithiocarbamates may be looked upon as derivatives of amines andcarbon disulflde, since the usual method of preparing them is byreacting an amine with carbondisuliide and caustic alkali:

The various polyvalent metal dithiocarbamates may be prepared from thealkali metal dithiocarbamates by double decomposition. The preferreddithiooarbamates may, therefore, be regarded as polyvalent metaldithiocarbamates derived from secondary amines and containing asuiliciently large hydrocarbon group or groups to render the saltsoil-soluble. The secondary amine or which the salt is a derivative maybe an allphatic amine (di-alkyl, di-cycloalkyl. mixed alkyl-cycloalkyl,eta), an aromatic amine or a mixed aliphatic-aromatic amine and it maybe an amine such as piperidlne or itshomologues in which the secondarynitrogen atom is part at a heterocyclic ring.

Illustrative examples oi'thiocarbamates that may be used in accordancewith the invention are calcium, lead, zinc and cadmium dibutyldithiocarbamates; zinc methyl octyl dithiocarbamate; zinc dicetyldithiocarbamate; sine diamyl thiolcarbamate; sinc diamylthionocarbamate; zinc monocetyl dithiocarbamate: zinc butyl amylphenyldithiocarbamate; calcium di- (cyclohexylphenyl) dithiocarbamate;calcium, zinc. cadmium and potassium "petroleum base" dithiocarbamates;zinc dibenzyl dithiocarbamate; zinc di-(cetyl- 'phenyl) dithiocarbamate;and zinc di-(amylpiperidyl) dithiocarbamate.

General methods of preparing thiocarbamates are available in theliterature. The best method presently available for preparingdithiocarbamates is that method in which a primary or secondary amine isallowed to react with carbon disulilde and aqueous or alcoholic causticsoda or caustic potash. producing an alkali metal dithiocarbamate. Thismay be recovered by crystallization, but since the polyvalent metalsalts are preferred, it will be the usual practice to add an aqueoussolution or a water-soluble polyvalent metal salt, such as calciumchloride or line sulfate, to the reaction mixture (diluted with water itnecessary) containing the alkali metal dithiocarbamate, therebyprecipitating the desired polyvalent metal dithiocarbamate. This may bepurifled by crystallization from a suitable solvent, such as a lighthydrocarbon thinner. Alternatively, to an aqueous solution or alkalimetal of dithiocarbamate may be added petroleum thinner and to themixture may be added an aqueous solution or a polyvalent metal salt.thus precipitating 5 polyvalent metal dithiocarbamate from aqueousacsasss 5 a solution and forming a solution of the same in petroleumthinner. General methods of preparing monothiocarbamates (which are oftwo types: thiolcarbamates.

and thionocarbamates, I

mmN-c-o-M) are available in the literature; e. 8.. thlolcarbamates fromamines and COS.

The preparation of petroleum base dithiocarbamates is described indetail in Miller and Rutherford application, Serial No. 441,064, filedMay 6, 1942 (now Patent No. 2,363,012, dated November 21. 1944). Brieflystated. the "petroleum base" dithiocarbamates are prepared by extractingthe nitrogen bases from nitrogen-containing cracked naphtha or the like,reducing the bases and reacting the reduced bases with carbon disulfideand caustic alkali to produce the alkali metal "petroleum base"dithiocarbamates, from which the polyvalent metal "petroleum base"dith'iocarbamates can be prepared by double decomposition.

From the properties and reactions of the reduced, cracked petroleumnitrogen bases from which the aforesaid "petroleum base"dithiocarbamates are derived, it is believed that they are complexmixtures predominating in piperidine derivatives. also containingtetrahydro quinoline (reduced nitrogen ring) and/or its derivatives.These bases contain alkyl substltuents, such as methyl, ethyl and propylsubstituents, on the carbon portion of the ring. The dithiocarbamatesproduced from these bases, that is, the aforesaid "petroleum base"dithiocarbamates. are, therefore, believed to be a mixture of compoundsof the formula Gila-Cg: B N-- -S-.M

CHr-C 1 wherein M is a metal and one or more of the hydrogen atoms aresubstituted by short alkyl groups (about 01 to C5) and/or by acondensedents on the carbon part of the ring. may also beused accordingto the invention.

The sulfonates 'hereinabove described may be used in oil in proportionsof 0.1 per cent or less to 5 per cent or more, about 0.5 to 1.5 per centbeing preferred, and the thiocarbamates may be used in oil inproportions of 0.1 per cent or less to 2 per cent or more, about 0.5 to1.5 per cent being preferred. All percentages so stated are by weightbased on finished oil. Concentrates of sulfonate and thiocarbamate inoil may be prepared for later blending with more oil to produce thefinished lubricant; for example, concentrates containing 10 to 50 percent of sulfonate and 10 to 50 per cent of thiocarbamate, suchpercentages being by weight based on total concentrate.

fonate. have been heretofore proposed as motor oil detergents. They are.however. unduly corrosivo toward hard alloy bearings suchv ascadmium-silver and copper-lead bearings and they do not satisfactorilyinhibit gum formation and deposition in piston rins slots. etc. I havefound that the sulfonates. such as calcium mahogany sulfonate. areconsiderably improved in these respects by the use o f thiocarbamates.such as zinc "petroleum base dithiocarbamates and zinc dibutyldithiocarbamate.

' The following specific examples will serve to illustrate theadvantages obtainable by and the preferred manner of practicing theinvention.

Example 1-Lauson engine tests-Various oils were subjected to test ascrankcase lubricants in single cylinder Lauson gasoline engines of thekind described in Parrington et al. U. 8. Patent No. 2,325,597. Engineswere operated at 1200 revolutions per minute. 875 1''. jackettemperature, 300 1''. oil temperature and for 60 hours. After each runthe engine was disassembled, inspected, cleaned and reassembled.

The manner of testing may be illustrated as follows: Assume that threeoils designated as I, II and III are under investigation. These oils aretested in the same engine; also tested in the same engine is a"reference oil," which is a standard, commercially available heavy dutylubricant containing as compounding agents a metal phenate and a metalorgano phosphate. The first run in the engine is with reference oil.then oils I. II and III are tested in that order, and, finally. thereference oil is again tested.

It is now known that an engine changes its characteristics duringoperation; thus an engine that has been run 60 hours will not, eventhough disassembled, cleaned and reassambled, give the same performancewith a fresh quantity of the same lubricant. To avoid as much aspossible errors in comparing oils due to the aforesaid change of enginecharacteristics. the following plan was used.

Suppose the "piston discoloration number" (PD No.), which is a form ofrating crankcase lubricants explained in detail hereinbelow. of thereference oil when first tested is 200, the PD Nos. of oils I, II andIII are 150, 1'15 and 200, respectively, and the PD No. of reference 011when last run is 250. An interpolated reference oil PD No. is calculatedfor each of the oils I, II and III. It is assumed, since the same enginegave a PD No. of 200 before oils I, II and III were run and a PD No. 250afterwards, or a diiference of 50 PD No. units, that if at the time oilI was actually tested the reference oil had been used, the PD No. ofreference oil would have been 200 plus one fourth of 50 or'212.5;similarly. that the PD Nos. of reference oil if used at the times oilsI11 and III were used would have been 225 and 237.5, respectively. Fromthese interpolated PD Nos. of reference oil and from the actual PD Nos.of oils 1, H and III are calculated PD No. diil'erences, each of thesebeing the difference between the actual PD No. and the correspondinginterpolated PD No.. the diflerence being positive if'the actual PD No.is greater, negative if it is smaller than the interpolated PD No.

This manner of rating oils is more accurate than a manner of ratingwhich simply compares actual PD Nos.. for it corrects in part at leastfor changed characteristics of the same engine and it makes morereliable the comparison of PD The sunonates. such as calcium mahoganysul- Nos. obtained in different engines.

7 "PD No.," an abbreviation of "piston discoloraticn number,"hereinabove and hereinbelow referred to, is arrived at in this manner:The engine is run as described for hours. Then it ute to the morewater-soluble, less oil-soluble character of the sulfonate.

, Example Zr-Full scale engine tests-Tests were carried out in two typesof full scale engine showing than the base oil. This result we attribisdisassembled. The piston skirt is inspected using as crankcaselubricants the preferred oils visually. To a piston skirt which iscompletely of the invention. The said engines and the conblack isassigned a PD Noiof 800; to one which ditions of operation were asfollows: One engine, is completely clean is assigned a PD No. of zero;preferred to herein as the "L-i' engine, was a to those intermediatecompletely black and comsingle cylinder, 5%" bore Diesel engine; it waspletely clean are assigned PD Nos. in proportion run for 480 hours at1000 revolutions per minute. to the carbonaceous deposits. Actually,further at a load of 10.8 brake horse power, oil temperarefinements wereemployed in arriving at PD Nos. tureof 145-150 F., jacket temperature of175- hereinbeiow disclosed. but since the same method 180 It, oil changeat 120 hour intervals. The was used in every case it is unnecssary todescribe other engine, herein referred to as the, Ii-3" entheserefinements. gine, was a 4 cylinder. 4%" bore Diesel engine Resultsobtained with various oils are set forth which was run for 120 hours at1400 revolutions in Table I below. per minute, BHP of 3'7, oiltemperature of 210- Tablel i i'ii' t'u Film m. 35' Sulionlto Additive mDithiooarbamate Additive m per figg'g;

- Ki 0 am Kilogram of u tron OI mahogany suliouste r 1 Zn petroieumbale'. eltnitmttmtttu' so i06 i 14 0 so -115 -do 1 Zndihutyldithioearhamate so 0 Ba mahogany suiionsts I 14 Zn "petroleumbass" dithiooarbamate- -i00 'Os "petroleum iatsri" benol sulionate. 15in 20 l Ca "petroleum slu gs" sul costs... 14 f 1) +215 Ca ietra-smylsuli'onate... 14 .d.o 20 +75 Ca mahogany sulionatell 14 M so 205 Cs"petroleum alkylsted" benzene lulionate. is o 00 M& I +400 to +500 I NoCompounding.

In Table I above. base oil A designates an SAE 214 F., jackettemperature of 198-202 R, no grade blended oil. a blend of solventtreated oil change. California naphthenic base oil and California par-Results are given in Table II below. afilnic base oil. Base oil Bdesignates a straight Table H SAE 30 grade California paraflinic baseoil. The concentrations are expressed as miliimols of metal per kilogramof compounded oil; thus, I millimols as A 8 of Ca mahogany sulfonate Iand 20 millimols of zinc "petroleum base" dithiocarbamate mean fi' fg 33mm No 0.007 and 0.020 gram mols of calcium (in form a Belt m M m ofsulfonate) and zinc (in form of dithiocarbamm 6 atg) per kilogram of31,] 0 Top Ring Groove De- Thin to Mad -1 Med to Hvy.

The calcium mahogany sulfonate I was the cal- H5, o 1 cium salt of amahogany acid obtained in the l m 1 sulfuric acid treatment of a blendof asphaltic io g 'gfim and paraflinic base oils to produce white oil;caiest: cium mahogany sulfonate II was the calcium salt as"m2sr'?iiifir%i i s: it'ii: d gd zrste.

of a mahogany acid obtained in the sulfuric acid 9% y"; 37 treatment ofa paraiiinic base oil to produce white with sr oil; the calcium"petroleum alkylated benzene andphenol sulfonates were the calcium saltsof on A consisted of base n Table 14 c sulfonic acids produced frombenzene and phenol, go mahogany Sultanate and 1% zinc a 32l'especflvelythat had been d f base" dithiocarbamate. Oil B differedfrom oil White 011; and the calcium Petroleum Aonlyinthat it containedhaliasmuch sulfonate. sl d 1111 11 w the calcium Salt of u 'Thereference oil was the same as described in fonated phenol extract ofpetroleum, said sul- Example 1, muted extract being 9 Water-soluble IndThe same three oils were also-subjected to 'a less oil-soluble characterthan mahogany'sulfonlc foaming t t-1 which oil is pumped from themldflcrankcase of a 1% horsepower Wisconsin single I It is pparent fromTable I that the sulfonatecylinder air-cooled gasoline engine to anevacudlthlocalbamate mp ndin greatly imp v ated flask where the heightof foam is measured, h base 011 and in most ases yi a uch 7e thence backto the crankcase. From data oblower PD'NO. than the reference 11- I 1 8-served in this test a foamindeiv' is calculated. niflcant that thecalcium "petroleum sludge" sul- This foam index measures both thefoaminess of fonate-zinc "petroleum base dithiocarbamate an oil at anabsolute pressure of 5" mercury and compounding made a poor showingcompared the extent to which the pressure can be reduced with thereference 011, although a much better before foaming becomes universalthroughout the body of oil in the flask. R su ts, both in height of foamand.i'oam index, are given in Table III below.

Table "1 Height oi loam in inches at 5" marcury absoluteprecaurc 2.0

1.8 3.6 Foam index 8.0 1.2 85-}- Further examples of compounded oils'otthe invention are as follows:

Iteierencc on n on 5 major proportion of a petroleum oil of lubricatingviscosity, about 0.1 to 5% by weightbased on finished oil of anoil-soluble alkaline earth metal Base Oil Sultanate Thiocerbamate BAEhthenic oil 1 Ba 1 Zn lcum base" dithiocal'bamato. SAE war afiinic oil.l Camah y sulionate 1 0. 531.: base" dithiocarbamate, BAE 30 mixed baseoil 1 Ca out 1 t. mnmn i 1, Ba butyl dithiocar bamate. SAE 30Pennsylvania oil- 1 a Ca ogany sulionate i 0d "petroleum baledithiocarbamate.

ofls, more particularly with crankcase lubricating 25 oils; however, theemployment of the compounding agents of the invention in otherlubricants, in

transformer oils, in greases, etc., is contemplated.

I claim:

0 high molecular weight aliphatic type alkaryl sulionate and about 0.1to 2% by weight based on finished oil of an oil-soluble zincdithiocarbamate.

5. The petroleum lubricating oil 0! claim 4 wherein the alkaline earthmetal is calcium.

6. A petroleum lubricating oil comprising a major proportion 01' apetroleum oil oi lubricating viscosity, about 0.1"to 5% by weight basedon finished oil of calcium mahogany sulfonate and about 0.1 to 2% byweight based on finished oil 1. A petroleum lubricating oil. comprisinga so of zinc "petroleum base dithiocarbamate.

major proportion of a petroleum oil 0! lubricating viscosity, about 0.1to 5 per cent by weight based on finished oil of an alkaline earth metalmahogany sultonate and about 0.1 to 2 per cent JAMES o. CLAYTON.

REFERENCES CITED The following references are or record in the by weightbased on finished oil of zinc "petroleum m of t patent:

base" dithiocarbamate.

2. A petroleum lubricating 011 comprising a major proportion ofpetroleum oil of lubricating viscosity, about 0.1 to 5 per cent byweight based on finished oil of an oil-soluble calcium higher 402,265,851

alkaryl sulfonate or above about 500 molecular weight and of thealiphatic type in which at least by weight or the sulphonic acidconsists of aliphatic carbon and hydrogen and about 0.1 to

UNI'I'ED STATES PATENTS Number Name Date 2,100,880 Loane June 8. 1989llatheson Dec. 0, 1041 2,343,393 Bergen Mar. 7, 1944 2,361,478 HigbeeOct. 81, 1944 2,386,539 McCleary Jan. 2, 1945 7 Patent No. 2,450,633.

Certificate of Correction October 5, 1948.

I JAMES O. CLAYTON It is hereby-certified that error appears in theprinted specificetion of the above numbered patent requiring correctionas follows:

Column 10 lines 20 and 21, claim 4, strike out high molecular weightaliphatic typealkarylsuifonate and insert instead higher alkarylsulfonate 0 above about 500 molwular weight and of the aliphatic type inwhich at least 50% by weig t of the sulphonic acid consists of aliphaticcarbon and hydrogen; and that the'said Letters Patent should be readwith this correction therein that the same may conform to the record ofthe case in the Patent Oflice.

, Signed and sealed this 25th day of January, A. D. 1949.

I [out] THOMAS E. MURPH Alcictmit 0mm; Patmtl.

